Local node module (not npm registry) does not load with --node_modules-dir flag

[abflow]

I have a node module test_node which is locally installed within the deno project into a node_modules folder via:

npm install --save ../test_node

package.json:

{
  "dependencies": {
    "test_node": "file:../test_node"
  }
}

When I run with the node-modules-dir flag:
deno run -A --node-modules-dir index.js

I get the following error:
error: npm package 'test_node' does not exist

[abflow]

Ok, I had previously used into my index.js file:

import Test from "npm:test_node";

But now, when I simply use:
import Test from "test_node";

this time, I get the following error:

error: Parsing version constraints in the application-level package.json is more strict at the moment.
Not implemented scheme 'file'

[abflow]

One workaround could be to use the import map for loading a local node module without using npm install.

That would be possible if deno could somehow deduce internally from the import map value that it has to deal with a node module:
deno.json

{
	"imports": {
		"npm:test_node": "../test_node/index.js"
	}
}

error: Uncaught SyntaxError: The requested module 'npm:test_node' does not provide an export named 'default'

{
	"imports": {
		"npm:test_node": "../test_node"
	}
}

error: Accès refusé. (os error 5)

{
	"imports": {
		"npm:test_node": "../test_node/"
	}
}

error: Module not found

[abflow]

Though it is confusing from a node.js perspective, this is a minor issue, so I close it.

[jsejcksn]

@abflow I didn't find anything indicating that this has been resolved, so I don't think it should be closed — AFAICT, Deno can't yet load Node modules from the local filesystem.

Ref: https://deno.land/[email protected]/node/package_json

Repro:

Local Node module

./local_tools/package.json:

{
  "name": "local_tools",
  "version": "0.1.0",
  "type": "module",
  "main": "index.mjs"
}

./local_tools/index.mjs:

export { default as shout } from "./shout.mjs";

./local_tools/shout.mjs:

/** @param {string} text */
function shout(text) {
  console.log(text.toUpperCase());
}

export default shout;

Deno app

./deno_app/package.json:

{
  "name": "deno_app",
  "version": "0.1.0",
  "dependencies": {
    "local_tools": "file:../local_tools"
  }
}

./deno_app/main.ts:

import { shout } from "local_tools";

shout("hello world");

In the terminal

% pwd           
/Users/deno/example/deno_app

% deno --version
deno 1.32.3 (release, aarch64-apple-darwin)
v8 11.2.214.9
typescript 5.0.3

% deno run main.ts
error: Parsing version constraints in the application-level package.json is more strict at the moment.

Not implemented scheme 'file'
    at file:///Users/deno/example/deno_app/main.ts:1:23

[denizdogan]

I agree with @jsejcksn, and I don't think this is a minor issue, I'd say it's a pretty major issue, especially considering #18616. It seems that Deno can handle neither private npmjs packages nor local Node.js packages.

[abflow]

@jsejcksn @denizdogan You're right... sorry about that. I reopen the issue.

[festusyuma]

Hello, is there any update on this issue. Thank you

[dsherret]

No, there was a bit of work done on the patch feature for JSR (#25068), but not for npm yet (I tried, but cut it out of the scope of the initial implementation).

[maheshbansod]

Are there any work-arounds? - this would be helpful for testing/debugging an NPM library with a deno project locally.

[SebastienGllmt]

I found a hacky workaround for this

1. Set "nodeModulesDir": "auto", in your root deno.json (this will get a node_modules folder generated)
2. Place your local dependency somewhere on your disk (say file path ./my-dep)
3. Create a symlink from your folder to your node_modules

Here is an example of a deno task you can run to create the symlink assuming you placed the local dependency at the root of your deno project

"link:my-dep": "bash -c 'if ! [ -L ./node_modules/my-dep ]; then ln -s ../my-dep ./node_modules/my-dep; fi'",

WARNING: this may not always work. Notably, it has two downsides:

1. You will have to relink if you ever clear your node_modules (I don't think there is a good way to do this automatically for a local folder given deno's lack of non-npm postinstall script support)
2. This won't update your deno.lock (although presumably fewer things depend on this file being accurate)

[DreamwareDevelopment]

Trying to use Deno in Nx, total nightmare, thought this may help.